As mobile communication and radio access technology are finding widespread use, various radio communication systems such as cellular communication, wireless LAN, and DSRC (Dedicated Short Range Communication) have come into existence. To further advance these existing radio communication systems, including an increase in communication speeds, the functions of the radio communication system will be added and changed. In addition to these existing radio communication systems, a study is being made to come up with new radio communication systems, such as MBWA (Mobile Broadband Wireless Access) being drawn up in the IEEE802. 20 Committee.
A possible radio communication apparatus to cope with such situations in which diversified radio communication systems exist is a software defined radio. The software defined radio is a radio communication apparatus that can accommodate various radio communication systems by modifying software.
Generally, the processing amount of signal processing of radio communication is extremely large. Accordingly, a high signal processing capability is requested for the software defined radio. Therefore, a study is being made of a method of configuring the software defined radio with hardware provided with plural processors.
A method of configuring a software defined radio using hardware provided with plural processors is disclosed in JP-A No. 283651/2003. The construction of a software defined radio disclosed in JP-A No. 283651/2003 is shown in FIG. 14. For example, in the case of receive, a radio signal received in an antenna 1 is subjected to signal processing for demodulation in a radio transceiver 2, a signal processing circuit 3, a second processor 21, and a first processor 11, and then is outputted from an input-output device 15 through a bus 4B. On the other hand, in the case of transmission, a transmission signal inputted from the input-output device 15 is inputted to the first processor 11 through the bus 4B, further subjected to signal processing in the second processor 21, the signal processing circuit 3, and the radio transceiver 2, and then transmitted from the antenna 1.
In JP-A No. 283651/2003, a software defined radio to which a third processor is added as shown in FIG. 15 is also disclosed. In this case, a signal transmitted and received is subjected to signal processing in a third processor 31 in addition to the antenna 1, the radio transceiver 2, the signal processing circuit 3, and the second processor 21, and the first processor 11, and inputted and outputted to and from an external device in the input-output device 15 through the bus 4C. Moreover, in this case, the second processor at least controls the signal processing circuit 3.